305-21831:7277+13323•(5484-5477):31087

Result: 305

Steps:

• Interpret ":" as division and "•" as multiplication. So the expression is 305 - (21831/7277) + (13323*(5484-5477)/31087).
• 5484 - 5477 = 7; 133237 = 93,261; 93,261/31,087 = 3 (since 31,087 = 74,441 and 93,261 = 713,323 = 4,4413).
• 21831/7277 = 3 (since 7277*3 = 21,831).
• Therefore: 305 - 3 + 3 = 305.